5.3 coolant / over heating
Thread Starter
Staging Lane
Joined: Feb 2020
Posts: 79
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5.3 coolant / over heating I have an '04 5.3 out of a Yukon that's getting hot fast. I have it plumbed directly to the radiator, with no overflow tank. I'm not sure if there's an air bubble somewhere or if the T stat is bad. Is there a trick to get air bubbles out of the system? Or do I need the overflow tank?
Thanks !
Thanks !
TECH Senior Member
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From: Central Cal.
Raise the front of your vehicle off the ground a few inches. Disconnect the upper hose from the radiator and fill thru the hose. The angle should allow air to travel to the front of the engine.
Thread Starter
Staging Lane
Joined: Feb 2020
Posts: 79
Likes: 1
Do I need the overflow tank?
I have the 1/4" line that comes off the steam port, going through the TB connections then directly to the 1/4" nipple on the radiator by the cap. Is that correct? Or does that 1/4" need to go to an overflow tank?
I have the 1/4" line that comes off the steam port, going through the TB connections then directly to the 1/4" nipple on the radiator by the cap. Is that correct? Or does that 1/4" need to go to an overflow tank?
Andrew
You CANNOT hook the steam line to the nipple on the radiator that goes to the overflow tank if thats the fitting you're referring to. That nipple is on the wrong side of the cap. You need the steam hose going into the radiator tank,, radiator hose or waterpump if you want to drill and tap for it. You don't necessarily need an overflow tank though, however without the original surge tank, you MUST fill the engine through the upper radiator hose, otherwise the coolant will stop at the thermostat and not fill the engine block.
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Thread Starter
Staging Lane
Joined: Feb 2020
Posts: 79
Likes: 1
You CANNOT hook the steam line to the nipple on the radiator that goes to the overflow tank if thats the fitting you're referring to. That nipple is on the wrong side of the cap. You need the steam hose going into the radiator tank,, radiator hose or waterpump if you want to drill and tap for it. You don't necessarily need an overflow tank though, however without the original surge tank, you MUST fill the engine through the upper radiator hose, otherwise the coolant will stop at the thermostat and not fill the engine block.
sounds like that's my issue then. I'll return the steam port back into the radiator hose.
Thanks for the help! This has been a hell of a learning curve.
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Actually, you still have lots of possibilities. How are you determining that 'it's getting hot fast'? If a sender/gauge is involved, are you certain the sender and/or gauge is accurate? Did you test the t'stat before starting the engine - pot of water on the cooktop and a thermometer? While the steam line should be hooked up as described above - I doubt that's causing a quick overheating situation. But when filling the system, air gets pushed out through the steam ports so having them connected somewhere that allows that to happen is helpful.
The coolant in the system expands and contracts with temperature. You either leave it low in the radiator tank, or it's gonna expand and push out of the cap/vent and end up everywhere. Overflow tank preferred. Even better a pressurized reservoir with steam ports plumbed into the air space at the top of the reservoir....
The coolant in the system expands and contracts with temperature. You either leave it low in the radiator tank, or it's gonna expand and push out of the cap/vent and end up everywhere. Overflow tank preferred. Even better a pressurized reservoir with steam ports plumbed into the air space at the top of the reservoir....
Last edited by Michael Yount; Aug 4, 2020 at 10:14 AM.
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From: Central Cal.
Thread Starter
Staging Lane
Joined: Feb 2020
Posts: 79
Likes: 1
You CANNOT hook the steam line to the nipple on the radiator that goes to the overflow tank if thats the fitting you're referring to. That nipple is on the wrong side of the cap. You need the steam hose going into the radiator tank,, radiator hose or waterpump if you want to drill and tap for it. You don't necessarily need an overflow tank though, however without the original surge tank, you MUST fill the engine through the upper radiator hose, otherwise the coolant will stop at the thermostat and not fill the engine block.
can I come out of the pass side steam port ( yes, pass side and drivers side are connected) and go right to the upper coolant hose?
You can actually drill and tap the side of the water pump and just run the steam line back into the water pump.
If you have the heater hose ports on the water pump blocked off, I also recommend drilling a small hole in the thermostat or right next to the thermostat. This keeps a small amount of water circulating by the thermostat and it will open and close more consistently.
My car runs at 195 with the stock t stat and never moves.
Also, how you bleed the system of air will really help with air bubbles. I tend to fill it with the front of the car jack up in the air. I’ll leave the steam ports lose and fill it till all the air is gone and have only coolant coming out of the steam ports. Then tighten them down and top it off the rest of the way.
Thread Starter
Staging Lane
Joined: Feb 2020
Posts: 79
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Ok... I don't know if I'm an idiot or WTF is going on. This thing is still getting hot. I filled the system like you guys reccomended. Trough the upper hose untill fluid came out the steam port. Then filled the rad. I ran the car, the upper hose is hot. Can't touch it. The lower hose is cold, not even warm.
I didn't drill the t stat ( don't know what size hole or where to drill) it's a new T stat.
do I have it plumbed wrong? The lower rad hose goes to the T stat, the upper rad hose goes to the other port on the water pump.
The other issue is my fan isn't coming on. PCMofNC setup the ECU to turn on the fan.
to me it seems like the t stat isn't opening, circulating the fluid. How the hell do I get the t stat to open !
I didn't drill the t stat ( don't know what size hole or where to drill) it's a new T stat.
do I have it plumbed wrong? The lower rad hose goes to the T stat, the upper rad hose goes to the other port on the water pump.
The other issue is my fan isn't coming on. PCMofNC setup the ECU to turn on the fan.
to me it seems like the t stat isn't opening, circulating the fluid. How the hell do I get the t stat to open !
Just because it's a new thermostat does not mean it's a good one, I've had that happen to me a couple times so you might try testing it. I just bring a pan of water to a boil and drop it in and see if it opens. As far as drilling the thermostat, I just drill a BB size hole, The thermostat is to regulate the minimum temperature so a small hole will just mean it will take slightly longer for it to get up to operating temperature and has no effect on maximum temperature.
What I usually do is fill the system and start the engine and pull the steam line loose (near the engine) until I get a steady stream out of it and then put it back on.
What I usually do is fill the system and start the engine and pull the steam line loose (near the engine) until I get a steady stream out of it and then put it back on.
Thread Starter
Staging Lane
Joined: Feb 2020
Posts: 79
Likes: 1
trust me, I do. I'll probably have to send him a case of beer for all the help he's given me through out this swap.
this coolant issue is the last thing stopping me from getting this '53 Cadillac back on the road where it belongs...
this coolant issue is the last thing stopping me from getting this '53 Cadillac back on the road where it belongs...